Electric heater



FIG. 1. is a top, front right side perspective view thereof;

FIG. 2. is a front elevational view thereof;

FIG. 3. is a rear elevational view thereof;

FIG. 4. is a left plan view thereof;

FIG. 5. is a right plan view thereof;

FIG. 6. is a top plan view thereof; and,

FIG. 7. is a bottom plan view thereof. 

The ornamental design for an electric heater, as shown and described. 